Dynamic Changes And Effects Of IL-31 In Lung Tissues Of Experimental Mice With Pulmonary Fibrosis

Objective To determine the expressions of IL-28B in lung tissues of mice with pulmonary fibrosis(PF) induced by bleomycin at various periods and ones treated with prednisone;to study the effects of the cytokine in the pathogenesis and diagnose of pulmonary fibrosis.Methods Seventy two male mice were randomly divided into three groups:control group(n=24),model group(n=24) and therapy group(n=24).The mice of control group were treated with normal saline(0.06-0.07ml) by intratracheal instillation,while the mice of model group and therapy group treated with bleomycin solutions.From the first day after bleomycin challenge,the therapy group was perfused intostomach prednisone(6 mg/kg) daily,and the other groups were given normal saline every day.The volume of the liquid perfused to every mouse was 0.2ml.On day 7,14,21, 28 after administration,6 mice of each group were sacrificed and the lung tissues were harvested.The pulmonary inflammation and fibrosis of mice in different groups were observed by pathological method.Hydroxyproline concentrations were examined.The expressions of IL-28B in lung tissue of mice were detected by method of western blot and RT-PCR.Results:1.It was observed in the slices by pathological method that the difference between the model group and the therapy group was not evident in the early period,but at the later period the fibrosis of the model group was more significant than that of therapy group.There were not inflammation and fibrosis in control group.2.Hydroxyproline concentrations in model group are higher than them in control group on day 14,21,28(P＜0.01). 3.The expressions of IL-28B mRNA and protein detected in lung tissue of model group were higher than that of control group and therapy group on the 7th,14th,21th day(P＜0.01),and peaked on the 14th day.In therapy group,the expression of IL-28B on day 7,14,21,28 showed no significant different within the control group.Conclusions:IL-28B may contribute to the pathogenesis of pulmonary fibrosis in early period.Detection of IL-28B is helpful to diagnose in early period.